Automatic riveting machine



Dec. 9, 1952 w. E. HARNESS ETAL 2,620,875

AUTOMATIC RIVEZTING MACHINE Filed July 1, 194a 7 Sheets-Sheet 1INVENTOR. WAYNE E. HARNESS y dorm O. HRUBY JR.

Agent W. E. HARNESS ETAL AUTOMATIC RIVETING MACHINE Dec. 9, 1952 7Sheets-Sheet 2 Filed July 1, 1946 m: m m W WAYNE E. HARN y dorm O. HRUBYIll " Aoent Dec. 9, 1952 w. E. HARNESS ETAL 2 7 AUTOMATIC RIVETINGMACHINE Filed July 1, 194a 7 sheet -sheet s IN TOM WAYNE HARNESS BY down0. Hnu

1952 w. E. HARNESS ETAL 2,620,876

AUTOMATIC RIVETING MACHINE Filed July 1, 1946 7 Sheets-Sheet 4 v mmvronsWAYNE E. HARNESS By Joan O. HRUBY JR.

Agent 1952 w. E. HARNESS ETAL 2,620,876

AUTOMATIC RIVETING MACHINE Filed July 1, 1946 7 Sheets-Sheet 5 INVENTORSv WAYNE E. HARNESS BY Joan O. HRUBY JR.

AUTOMATIC RIVETING MACHINE 7 Sheets-Sheet 6 ill! Filed July 1, 1946 MAu- G4 2 L V128 A mmvrozzs WAYNE E. Hmmsss By Jorm 0. Hum JR.

. 5 Agent Dec, 9, 1952 w. E. HARNESS ETAL 2,620,876

AUTOMATIC RIVETING MACHINE Filed July 1, 1946 7 Sheets-Sheet 7INVENTORJ' WAYNE E. HARNESS By JOHN O. HRUBY JR.

Agent Patented Dec. 9, 1952 UNITED STATE TENT OFFICE 11 Claims. 1

This invention relates to machines useful in the riveting of aircraftcomponents and other objects and assemblies, the invention havingparticular reference to an improved machine of this class that is fullyautomatic in operation and low in maintenance cost.

Machines have been developed for performing automatic rivetingoperations and have found a wide application in many industries.However, the prior machines were designed and constructed in such amanner that they required frequent repair. For example, the life of thepunches and dies was very short because the operating linkages allowedmisalignment resulting in ultimate breakage. The wearing of the linkagesand the breaking of the punches and dies necessitated frequent andprolonged shut-downs of the machines, and involved expensive repairexpenditures. The prior machines referred to also lacked adequateprovision for adjusting or setting the parts for the dimpling andriveting of material of different thicknesses, and much time wasrequired in making these adjustments.

It is an important object of this invention to provide an automaticriveting machine that will operate at a low maintenance cost. Themachine of this invention involves a minimum of mechanical linkages andparts subject to Wear, and accurate alignment of the punch and dies ismaintained indefinitely so as to practically eliminate the possibilityof breakage. The several operating and shifting mechanisms are actuateddirectly by fluid pressure units, which in turn, are under control of anelectronic system, there being no intermediate mechanism subject to wearand failure.

Another object of the invention is to provide a riveting machine that isoperable to automatically perform an entire sequence of operationsbeginning with the dimpling of the material and ending with theheading-up of a rivet inserted in a punched hole in the material, andthat may be selectively set or controlled to perform a single operationor an appropriate sub-sequence of operations. When set or conditioned toperform the full sequence of operations, the machine dimples thematerial, punches an opening therein, inserts a rivet in the opening andthen heads up the rivet, this series of acts being entirely automaticand initiated by simple depression of a pedal, or the like. When lessthan this complete sequence is desired, the machine may be easilyconditioned for successively performing the following individual or dualfunctions: (a) dimple and punch the work parts, or (b) insert and driverivets.

The selective control of the machine is effected by simply operating aconveniently located selector switch.

Another object of the invention is to provide a riveting machine of thecharacter referred to which is operable to successively dimple hard andrelatively hard alloys and materials. In the 'sequential operations, thesheets of material are first dimpled, and while the dimpled material isheld under compression by the'dimpling' dies, the punch is operated toform or punch an opening in the material. The retention of thecompression on the material at the dimple during the punching operationassures efiective punching of the work without the development of cracksand without distortion of the material, even in cases where the materialis tough and hard.

A further object of the invention is to provide an automatic dimplingmachine wherein the depth of the dimple to'be formed in the material orsheets, and the height of the driven rivets may be readily changed oradjusted to condition the machine for the riveting of material ofvarious thicknesses. These adjustments are easily and quickly made bymoving electronic contacts with respect to an actuating pneumatic ram,this movement being effected by adjusting knobs conveniently positionedat the front of the machine for this purpose.

A still further object of the invention is to provide an automaticriveting machine incorporating an improved and thoroughly reliableelectronic control system which is easily selectively set by theoperator to be sequentially operated by movement of the severalpneumatic pistons or rams during machine operation.

Other objectives and features of the invention will be readilyunderstood from the following detailed description of a typicalpreferred form of the invention wherein reference will be made to theaccompanying drawings in which:

Figure 1 is a side elevation of a riveting machine incorporating thefeatures of the invention with certain parts broken away to showinternal parts in vertical cross section;

Figure 2 is a fragmentary, elevation of the other side of the machinewith a portion broken away to illustrate the valves and associatedparts, being a view taken substantially as indi a d y line 22 on Fi ur3;

Figure 3 is a front view of the machine taken as indicated byline ,3 onF gure Figure 4 is an enlarged vertical sectional view of the means foractuating the punch taken as indicated by line 44 on Figure 3;

Figure 5 is an enlarged fragmentary vertical section of the lower anvilassembly and associated parts showing a work piece being dimpled;

Figure 6 is an enlarged fragmentary vertical section of the die andpunch assembly showing the punch in the actuated position;

Figure 7 is a view similar to Figure 6 showing a rivet being headed up;

Figure 8 is an enlarged fragmentary front view of the upper activeassembly of the machine;

Figure 9 is an enlarged fragmentary vertical section of the rivet guideor feed means;

Figure 10 is a fragmentary elevation view with a portion in crosssection taken substantially as indicated by line I0-l0 on Figure 8;

Figure 11 is a transverse sectional view taken as indicated by line Il-I l on Figure 9;

Figure 12 is an enlarged vertical sectional view of the main cylindertaken substantially as indicated by line I2-l'2 on Figure 1;

Figure 13 is a horizontal sectional view taken substantially asindicated by line l3-l3 on Figure 14;

Figure 14 is a vertical sectional view with certain parts in elevationtaken substantially as indicated by line l4-I4 on Figure 13;

Figure 15 is an enlarged sectional view of the diaphragm valve;

Figure 16 is a wiring diagram of the electronic circuit means; and,

Figure 17 is a combined wiring diagram and flow diagram of the principalcircuits and fluid pressure actuating means of the machine.

The features of the invention are capable of embodiment in machinesvarying considerably in size, design and application. We will hereindescribe the preferred form of the machine illustrated in theaccompanying drawings, it being understood that the invention is not tobe considered as limited to the details of this particular embodiment.

As best illustrated in Figure 1, the machine includes a frame or body IDof generally C shape having a base II, a lower jaw I2, and an upper jaw13. The forwardly extending jaws are spaced a substantial distance apartto receive the work and the body [0, or at least certain parts thereof,are hollow to contain working parts, etc. An upwardly projecting tubularboss I4 is provided on the lower jaw [2 adjacent its forward end toreceive the lower anvil, die and punch assembly to be subsequentlydescribed. The active work-engaging elements of the machine are arrangedon the forward portions of the jaws l2 and I3 and include a lower dieand anvil carrier l5, best shown in Figures 1 and 5. The carrier I5 isguided for vertical movement in the tubular boss 14 and its upperportion is tapered or frusto-conical. A socket I6 is formed in the upperend of the carrier 15 to receive the shank of a die [1, which isremovably secured therein by a set screw l8. The active upper end of thedie I! has a die cavity or recess 19 to aid in forming the dimples inthe work piece and to serve as an anvil or abutment in setting up therivets. The die I! is tubular, having a central tzertical opening forslidably receiving the punch The lower active assembly further includesa stripper 2| slidable on the exterior of the die 11. The stripper is atubular part presenting a horizontal upper end face engaging the underside of the work piece W. The lower portion of the die I! is externallyflared as shown in Figures 5 and 6, and the stripper 2! is correspond gy shaped so that downward travel of the stripper is limited by thecooperating flared parts. When the stripper is in its lowermostposition, its upper surface is flush with the top surface of the die Thecarrier [5, punch 20 and stripper 2! described above, are eachindividually operated by fluid pressure actuated mechanisms, preferablyin the form of pneumatic cylinder and piston means. The means foroperating the carrier 15, that is, for moving the carrier vertically,comprises a cylinder 23, a piston 24 operable in the cylinder andlinkage connecting the piston and carrier. In Figure 1 we have shown thecylinder 23 horizontally arranged within the lower jaw 12 so that therod 25 of the piston extends forwardly for connection with a suitabletoggle linkage 26. The linkage is anchored at one end in the jaw l2 andis secured at the other end to the die carrier l5. It will be seen thatupon forward movement of the piston 24 the carrier with its die I 1,moves upwardly, and upon rearward movement of the piston the carriertravels downwardly. Air pressure lines 21 extend from the opposite endsof the cylinder 23 to a four-way solenoid valve 28 mounted within thehollow frame jaw and controlled in the manner to be later described.

The means for operating the punch 20 includes a vertical cylinder 28attached to the forward side of the carrier [5 and a piston 29 whichoperates in the cylinder and which is provided with a rod 30 extendingdownwardly through a gland in the lower head of the cylinder, as shownin Figure 4. Spaced lugs 3| on the cylinder head carry a pivoted lever32. The lever 32 is arranged so that the piston rod 3!! acts downwardlyagainst its forward end and its rearward arm engages a rod 33 guided inan opening 34 in the carrier I5. An intermediate push rod 35 is slidablein the upper portion of the opening 34 and an upper push rod 36 slidablyenters the lower end of the tubular die I! to contact the enlarged lowerend of the punch 20. The punch 20 is yieldingly supported forretraction, but upon actuation of the piston 29 the punch is positivelyforced upwardly. A helical spring 31 is engaged under compressionbetween the upper end of the rod 35 and the enlarged lower end of theupper push rod 36. When the work piece W is placed on the die I!preparatory to the dimpling operation or the punching operation, itsweight presses the punch 20 downwardly to compress the spring 31.However, when the piston 29 is actuated downwardly the rods 33 and 35move upwardly to compress the spring 31 until the upper end of the rod35 engages a reduced stem 38 on the upper push rod 36, whereupon forceis positively transmitted to the punch 20 to form an opening in the workpiece. Upon the return or upward movement of the piston 29 the rods 33,35 and 36 are free to return to the normal lower positions. Flexiblelines 40 and w deliver air under pressure to the opposite ends of thepunch actuating cylinder 28. The lines extend to a solenoid operatedvalve 209 within the hollow jaw 12. The control for the valve 209 willbe subsequently described.

The means for operating the stripper 2| serves to yieldingly urge thestripper upwardly so as to press against the under side of the workpiece W around the female die 11. It is contemplated that spring meansmay be employed for this purpose, but we prefer to use pneumaticcylinder and ram units. Vertical cylinder bores 4! enter the taperingupper portion of the carrier 15 and plungers or rams t2 extenddownwardly into the bores as shown in Figure 5. The projecting upperportions of the rams 32' curve upwardly and inwardly and areconnectedwith the stripper M at diametrically opposite points by springclips 43. The air pressure for supplying the bores H is carried by anair pressure line 3 extending from a main supply line and the line t lis branched to communicate with the lower ends of thebores. It isdesirable to provide a suitable pressure regulating valve 66 in the lineM as shown in Figure ll, which may be set or adjusted to maintain justsufficient pressure in the bores ll to yieldingly urge the stripper 2iupwardly to free the work from the die ii at the completion of thedimpling and/or punching operations.

The upper active assembly carried by the body jaw I3 includes a dimplingshoe 17 and a riveting shoe 48; see Figures 12, 13 and 14. The shoe 4?has an upwardly sloping arm 19 and its lower portion is offset andformed to removably carry a male dimpling die 59. The riveting shoe ithas a similar arm 5! and is provided in its lower portion with avertical opening 52. In the preferred construction, the two shoes ll andare mounted for individual vertical movement and for simultaneoushorizontal shifting. The means for carrying the shoes includes shafts 5dslidably received in spaced vertical openings 53 formed in the forwardportion of the jaw 53. 59 of the dimpling shoe i! is fixed to the lowerend of one shaft 5 3 and the arm 5i or" the rivet ing shoe 48 is securedto the lower end of the other shaft. The shafts are tubular, and theirupper end portions are tapered to engage in correspondingly shaped seats55 in the openings 53 so as to limit upward travel of the shafts. Springmeans is provided to urge the shafts 5 to their uppermost portions wherethe respective shoes 'il and A8 are spaced clear of the work W and toreturn the parts to these positions after the several operations. Thesemeans include bolts or stems 56 extending through the tubular shafts 54and provided at their upper ends with nuts 5'! for engaging the topsurface of the jaw it. Helical compression springs 53 surround the stems58 within the shafts 54 and are engaged under compression between thelower heads of the stems and internal shoulders 59 formed in the shafts.and 48 are normally held in the upper retracted positions by the springs58.

Means is provided for shifting the shoes d! and 28 between inactivepositions and positions where they are in vertical alignment with thedie it and the main ram 8%. This mechanism includes lever arms 69 havingsliding spline connections 6i with the shafts 54 so as to allowindependent vertical shifting of the shafts while remaining in positiverotation transmitting relation to the shafts. The levers extend from theshafts in parallel relation and their ends are pivotally connected witha common link t2. As best shown in Figure 13, the lever arms @9 and thelink 62 are housed in the hollow jaw 3 for free movement therein andpiston n echanisrns are supported on the jaw for shifting the linkhorizontally to move the shoes between their two positions. Horizontalcylinders 83 and as are secured to the opposite sides of the jaw i3 andcontain pistons provided with rods 58 which extend into the jaw 3. Theshifting link. 62 has a lug 63' extending between the opposing innerends of the piston rods E8. An air pressure line 63 communicates withthe outer end of the cyl- The arm Figure 14 illustrates how the shoes llA inder 63 and a similar line 690 supplies air under pressure to theouter end of the cylinder 64. The parts are constructed and related sothat upon introducing air pressure to the cylinder 63 the riveting shoe4B is brought to the active position in line with the main ram 58, andupon supplying air pressure to the cylinder 64 the dimpling shoe-41 ismoved to its active position in alignment with the ram. It will beobserved that shifting of one shoeto the active position simultaneouslymoves the other shoe to a remote or inactive position.

h Work. mpline nd un n ec an sm further includes a main cylinder andpiston unit for actuatingthe above mentioned main ram 68. This unitincludes a, vertical cylinder 69 mounted on the forward endof the jaw 13where its central longitudinal axis is in coaxial relationto the die ll.A piston l0 operates in the cylinder and has a rod H extendingdownwardly through an opening in the jaw 13. The lower end of the rod Hcarries a chuck F2 for the ram 63. The lower end ofthe piston actuatedram 63 is engageable with the male dimpling die 50 to drive the samedownwardly against the work W when the shoe t! is in the activeposition, and is adapted to move downwardly through the riveting shoe 48when the latter is in its active position to drive the rivet as shown inFigure 7. In this connection, it will be observed that the shank of therivet is upset against the top of the punch 25 and the female die I! sothat vertical adjustment of the punch 20 controls the dimensions of thedriven rivet. A stop screw 13, shown in Figure 4, is threaded through anopening in the top ofthe cylinder 28-and is engageable by the piston 29to limit the downward travel of the punch 2t. Thus adjustment of thescrew 73 controls the position of the punch 20 for the rivetingoperations.

Referring again to the main cylinder, it will be seen from an inspectionof Figure 12 that a reduced rod or stem 15 extends upwardly from thepiston 10 and slidably passes through an opening in the upper head ofthe cylinder. A disc or washer It is secured on the upper end of thestem ES, and a helical spring 11 is arranged under compression betweenthe cylinder head and washer to return the piston l6 and the punch 68 tothe raised position when air pressure in the cylinder is released. Theprojecting stem (5, spring ll and disc 16 are housed within a suitablehood or cap 18 on the cylinder .68.

t is desirable to incorporate a mechanism for feeding rivets to theriveting shoe t3 and for introducing the individual rivets to the shoe.In the drawings we have shown a simple rivet feed comprising a hopper 30arranged adjacent the outer end of the body jaw l3 and designed toreceive and contain a considerable supply of rivets. The hopper 8i)discharges into a track defined by a, groove 8! in a track member 82 anda slot 83 formed in a plate 85. attached to the track member. The member82 slopes downwardly toward the shoe 48 and the rivets move by gravitythrough the track. The groove BI is formed to receive the heads of therivets, while the rivet shanks extend outwardly through the groove 83 asshown in Figures 9 and 11.

A rivet-selection or gate means is provided at the lower end at theabove described track and includes a shjftable gate 85 slidablyengegedbetween the lower end of the track member 82 and the upper end ofa rivet discharging element 36. The element 86 has a passage 87 forreceiving the rivets and for guiding them to the riveting shoe, when theshoe is in the retracted position. The entrance of the passage 81 isshaped so that the rivets swing or tilt to a position where their shankslead or point downwardly, and the rivets remain in this position as theytravel through the passage to the riveting shoe. As best shown in Figure10, the passage 81 is offset horizontally from the lower end of thetrack groove 8! and slot 83, and the gate 85 operates to shift therivets one at a time from the track to the entrance of the passage 81.The selector or gate 85 has a T-shaped notch 88 for receiving anindividual rivet and this notch is adapted to register with the track toreceive the rivet. Upon shifting of the gate, the notch comes intoalignment with the passage 81 to discharge the rivet. In Figure the gate85 is shown in the receiving position where the notch 88 has justreceived a rivet from the track.

Cylinder and piston means is provided to shift the gate from thisposition to the discharging position where the rivet falls from thenotch 88 and the passage 81. A cylinder 98 is attached to the trackassembly, and the gate 85 has a rod entering the cylinder. A piston 9Ion the rod operates in the cylinder 98 and an air pressure line 92communicates with the outer end of the cylinder. The air line 92 extendsto a solenoid operated three-way valve 93 shown in Figure 1'7, and anair line 928 continues from the valve 93 to the valve I14 to be laterdescribed. Air under pressure, supplied to the cylinder 98, moves thegate 85 from the receiving position of Figure 10 to the position whereit discharges the individual rivet into the passage 87. Spring means isarranged to restore the gate 85 to the receiving position of Figure 10when pressure is released from the cylinder 98. A yoke or bracket 94 issecured to the track assembly, and a helical spring 95 is engaged undercompression between the bracket and an end of the gate 85. It will beseen how the spring 95 automatically restores the gate 85 tothe positionshown in Figure 10 when the valve I14 is operated to discharge pressurefrom the cylinder 98.

In conditioning the machine for each riveting operation a rivet issupplied to the riveting button or shoe 48 by the track and gate meansjust described. This rivet is retained in the shoe 48 while the shoe isshifted into alignment Y with the main ram 68 and until it is forcedinto the opening punched in the work piece W. Thus it is necessary tosupport the rivet in the shoe 48 in position for engagement by the mainram 68 so it will be guided downwardly into the punched opening. Themeans for temporarily supporting the rivet in the shoe 48 is illustratedin Figure 7 and comprises a pair of diametrically opposite dogs 96. Thedogs 98 are shiftably supported in radial slots or openings 91 in thewalls of the tubular shoe and are movable toward and away from thevertical axis of the shoe. The opening in the shoe 48 is proportioned tofreely receive the head of the rivet and the inner ends of the dogs havesloping surfaces for engaging under the rivet head. The dogs are urgedinwardly to normally occupy positions where they will catch and supportthe rivet introduced into the upper end of the shoe. Leaf springs 98 onthe exterior of the shoe 48 urge the dogs 98 to the active positionsindicated in broken lines in Figure 7. The full lines of Figure 7 showthe dogs in their outermost positions with the ram 68 engaged in theshoe opening 52, Upon retraction of the ram from the shoe 48 thespringurged dogs 96 return to the positions where they are operable tostop and support the next rivet. It will be observed in Figure 7 thatthe lower end of .the main ram 68 is reduced in diameter to enter theshoe opening 52 and to have a downwardly facing shoulder 99 forcontacting the shoe 48. The shoulder 99, acting on the upper end of theshoe 48, moves the shoe downwardly against the work piece W to theposition illustrated in Figure 7.

As will be subsequently described, the work piece work W is securelyclamped between the male and female dimpling dies I7 and 58 during thepunching operation, and the punch 28 is operated upwardly to punch theopening in the dimpled material. Figure 5 shows the parts in positionfor the pimching operation, and Figure 6 illustrates the punch in itsfully operated position. It will be seen that the upper or male die 58has a central opening I88 for receiving the punch 28 as it movesupwardly through the work part. The punch 28 displaces slugs S ofmaterial upwardly through the opening I88 as it forms the opening in thework piece. Means is provided for clearing the slugs from the openingI88 of the die 58. A lateral opening I8I joins the upper end of theopening I88 and an air pressure nozzle I92 is threaded in an alignedopening in the die 58 to discharge a stream of air across the top of theopening I88 and through the opening I8I. As shown in Figure 6, the slugsS on the top of the punch 29 are carried to a position adjacent thenozzle I82 so that the jet of air blows the slugs out through theopening I8I. An air line 183 leads from a four-way diaphragm valvc I04,to be subsequently described, to the nozzle I82. The line I83, or atleast the portion of the line adjacent the shoe 58, is flexible so thatit does not interfere with free movement of the shoe.

The elements thus far described are fluid pressure operated in theembodiment illustrated being pneumatically actuated, and the inventionprovides a versatile, dependable electronic control system for obtainingautomatic, sequential and independent actuation of the severalmechanisms to perform the dimpling, punching and riveting functions. InFigure 16 we have illustrated what may be termed the internal electroniccircuit which comprises an initiating stage A, a plurality ofintermediate stages B, C, D, E, F and G, and a reset stage H. Theinitiating stage A includes a thyratron or gas filled triode tube I85having a current limiting resistor I86 connected in its grid circuit anda surge protection condenser I8! tapped into the grid lead. A relay orswitch means is provided to initiate firing of the tube I85. As shown inFigure 17, this means comprises a relay I88 which is initially ornormally open, and a condenser I 89 is connected with one pole of therelay. A lead 9 extends from another pole or contact of relay I88 toterminal A The grid of tube I85 is connected with the lead 9. A D. C.power source III is provided to give bias for the control of the gridsof the tubes in the various electronic stages. A common line IID extendsfrom the negative side of the bias source I II to a limiting resistor 8of high enough resistance to allow condenser I89 to temporarily bringthe bias on tube I 85 to a voltage low enough to render tube I85conductive. Resistor 8 is connected between lines 9 and I I8. When therelay I88 is in the open condition, its associated condenser I89 has azero charge. Upon operation of the relay I 88 which may be effected bydepressing a foot pedal I54 (see Figure 17), the zero charge 9 isimpressed on the grid of tube IE5, firing the tube, or in other words,rendering the tube conductive.

The initiating'stage A further includes a relay I I3 having three postsor terminals A A and A for connecting with external circuits, which willbe later described. One side of the relay winding is tied into the plateof the tube I 35 by line I I9 and a lead I28 connects the other side ofthe winding with a suitable power supply I 22 through a networkIZSi-IE-I to be later described. One blade or contactor I Id of therelay is initially in a position where it electrically connectsterminals A and A and upon energization of the relay, this connection isopened and the 'contactor connects terminals A and A The second movableblade or contactor I I of the relay initially makes electricalconnection between a terminal I It'tied into the bias source III throughlead He and a lead iI'I. Upon energization of relay I I3, contactor SISbreaks this connection and moves to a position where it connects thelead I II with the terminal of a potentiometer lit. The other terminalof the potentiometer is connected with a grounded timing switch I2I. Avoltage limiting resistor I23 is interposed in the power line I26 and apeak charge condenser I24 is tapped off the line 52$ to ground at apoint between the resistor and the relay H3. The function of the abovedescribed elements will later become apparent The initiating stage A isassociated with the intermediate stage B to control actuation thereof.Referring again to Figure 16, intermediate stage B comprises a thyratrontube I25 having a lead I25 extending from its grid and provided with acurrent limitin resistor I21. The lead I26 extends to a terminal B whichhas connection with an'extern'al circuit to be later described. Therelay I28 of the first intermediate stage B has one terminal of itsactuating winding connected with the plate of tube I25 and a lead I 28connects the other terminal of the winding with the power line I29. Avoltage limiting resistor I BI is interposed in the line I29 and a peakcharge condenser I 32 is connected to the line at a point between therelay coil and the resistor. The relay of stage B is similar to therelay of the initiating stage A and includes a blade or contactor I33initially in a position where it connects terminals B and B Uponenergization of relay I28, the contactor I 33 breaks this connection andelectrically connects terminals B and B The second blade I36 of therelay initially makes connection between a terminal I34 in the bias lineI It and a line I35 extending to the timing resistor condenser circuitof the next intermediate stage 0. Upon energization of relay I28, theblade I36 breaks this connection and completes a circuit between saidline I35 and a terminal of a timing potentiometer I31. A switch I33 isconnected between the other terminal of potentiometer I37 and ground.The above described lead III extending from blade H5 of relay II 3connects with the grid lead of tube I25 and with a timing condenser I69.A maximum timing resistor MI is associated with condenser I48. Condenser!db and resistor It! are operable to timeout the tube I25 as will bedescribed below.

New referring again to initiating stage A, it will be assumed thatinitiating relay I538 is operated to fire tube IE5 as described above.In the event switch I 2i is closed at this time, firing of tube I 85energizes relay II3 to complete a circuit through terminals A and Aandto complete a circuit from condenser Mai through potentiometer us to10 ground. Completion of the circuit through the potentiometerdischarges the charge in condenser M0 to the extent that tube I25 of theintermediate stage B becomes conductive to energize relay I28 of stageB. This timing-out of tube I25 is controlled primarily by potentiometerI I8, resistor l' ii being of an extremely high value with respect tothe potentiometer. Thus it will be seen that if switch I 2i is closedwhen relay I I 3 is energized, timing-out of the tube I25 is determinedby the setting of potentiometer II 8. In the event switch I2! is openwhen tube I of initiating stage A becomes conductive, energization ofrelay II3 brings the maximum timing circuit comprising condenser H36 andresistor I II into play. Because of the value of resistor IGI, the tubeI25 of stage B is held nonconductive for a substantial period for thepurpose to be later described.

Intermediate stages 0, D, E, F and G may be identical with intermediatestage B just described, and are related one to the other in the mannerin which stage A is related to stage B. Accordingly, in orderto'simplify the disclosure, the details of stages C, D, E, F and Cr areomitted from the drawings, andin referring to theelements ofthesestages, reference numerals will be used corresponding to thereference numerals applied to corresponding elements of stage Bwithtl'ie' respective exponents C, D, E, F and G added thereto. However,in the case of the external terminals of stages C, D, E, F and G,th'ese'are designated C C C and C D D D andD and so on, as clearlyappears in Figure 17.

When lead I28 is energized before the-machine is operated, condensersI24, I32 and I32 to I32 inclusive are charged to the maximum peakvoltage of power supply I22. When tube I05 becomes conductive, the peakcharge of condenser I 24 is available for quick energization of relay II 3. Upon energization of relay II 3, the'charge is partially drainedoil from the condenser and resistor I23 becomes part of a dividingnetwork lowering the continuous voltage applied to relay I I 5. Thisallows the relay to remain energized without overheating. The peakvoltage networks I3I, ISI to ISI and I32, I32 to I32 of theseveralintermediate stages 13 to G inclusive, function in a similarmanner when their respective tubes I25 and I25 to IZE inclusive becomeconductive.

The several stages A to G inclusive are interconnected in the followingmanner, as shown in Figure 17. A conductor or lead 2I3 extends from apower supply line I92 to terminal G of stage G. Relay I 28 normallyconnects terminal G with terminal G An interconnecting line 2M connectsterminal G with terminal F of stage F. Relay I28 normally connectsterminals F and F and an interconnecting line 2I5 joins terminals F andE Relay I23 normally connects terminals E and E and an interconnectingline 2H3 joins terminals E and D Relay IZB normally connects terminals Dand D anda line 2H joins terminals D and C Relay I23n0rmally connects Cand C and a line 2i 8 joins terminals C and B Relay I28 initiallyconnects terminals E and B and a connecting-line 2H3 joins terminals Band A Terminal A is connected with terminal A by the contactor H4 ofrelay '5 it when the same is in itsd'e-energized condition. -t will beseen that this arrangement interlocks'the several stages in such amanner that delivery of current to their respective terminals 2' and ddepends upon-the position of their relays.

' The internal electronic circuit further includes a reset stage H forbreaking the full wave D. C. voltage from the power source I22 to thetubes 295, I25, I25 I I25 I25 and I25 and for discharging the severalcondensers I24, I32 I32 I32 I32 and I32 to render the related tubes ofstages A to G inclusive, non-conductive, thereby restoring these stagesto their normal or initial condition. Reset stage H includes agas-filled triode 0r thyratron tube I42 having a current resistor I21 inthe portion of its grid circuit extending to its terminal H The lead I35from the relay blade I 36 of stage G taps into the grid lead, andextends to a timing condenser I40 A maximum timing resister I4I isassociated with the ground condenser I40 It will be seen from aninspection of Figure 16 that tube I42 of reset stage H becomesconductive in the same manner as the tubes I25 of the intermediatestages, either through the timing-out action of potentiometer I31 orresistor I4I The reset stage H further includes a relay I43 connectedbetween the plate lead I44 of tube I42 and a lead I45 extending from thehalf-wave portion of power source I22. A current-limiting resistor I46is interposed in lead I45 and a smoothing condenser I41 is connected inthe lead across the winding of relay I43. The relay has a contactor orblade I48 connected with a terminal of above described line I20 andoperable between a position where it engages a grounded pole I49 and apole connected with a line I50 carrying full wave voltage from the powersupply I 22. When the relay I43 is in the de-energized condition, theblade I48 is in engagement with the terminal of line I50.

When the tube I42 is made conductive as described above, the relay I43breaks the full wave D. C. voltage circuit to the tubes I05, I25 and I25to I25 inclusive. Energizing of relay I43 also brings the blade I48 intoengagement with the grounded post I49 to discharge condensers I24, I32and I32 to I32 inclusive, rendering the tubes of several stages A to Ginclusive, nonconductive and allowing their related relays II3, I28 andI28 to I28 inclusive, to restor to their initial positions. Restorationof relay I 28 applies full negative voltage from source I I I to tubeI42 of stage H, making the tube nonconductive. This restores relay I43and completes the full sequence cycle. It will be observed that theinternal electronic circuit is automatic upon closing of the switch I54to carry out a full sequence of operations throughout the several stagesA to H inclusive. A case I56 mounted on a side of the body I0 containsthe above described electronic stages A to H inclusive, and the powersupply means I22.

The external circuits of the system include a master switch I52 forcontrolling delivery of current to the power supply I22. An indicatorlamp I53 may be exhausted with the power supply to indicate the positionof the master switch. The above described initiating relay I08 isconnected in series with a pair of pedal operated switches I54 sorelated that depression of a common pedal closes both switches. A safetyswitch I55 is also connected in series with the foot switch I54 andrelay I08, and is operated to allow heating of the tubes of stages A toH inclusive. The above described solenoid valve 28 for controllingdelivery of air under pressure to cylinder 23 has one lead 2I0 extendingto the power supply and has another lead I58 extending to a switch I59connected with a second power lead I60. The switch I59 is a double poleswitch and is also connected in series with the foot switch I54, safetyswitch I55 and relay I08. Thus in order to condition the machine foroperation, the switch I59 must be closed to actuate the piston 24, whichbrings the anvil or carrier I5 to its raised operative position.

With the switches I55 and I59 closed, the foot switch I54 is closed toinitiate operation of the machine. Closing of the switch I54 energizesrelay I08, which applies D. C. current to all stages A to H inclusive,of the internal electronic circuit, and applies a zero charge of thecondenser I01 to the grid of the tube I05 of initiating stage A. Asabove described, this fires tube I05 and actuates relay II 3 of stage A.A lead I10 extends from post A of stage A to a relay I1I which has apole and blade I12 interposed in a power line I13 extending to asolenoid operated four-way valve I14. Upon firing of tube I05 of stageA, relay IN is energized and solenoid valve I14 is reversed or operated.Solenoid valve I14 is operable to connect an air pressure supplymanifold I15 with the pipe 690 leading to the right-hand shiftingcylinder 64 so that the piston therein is operated to shift the dimplingshoe 41 into alignment with the main ram 68. This actuation of solenoidvalve I14 also supplies air under pressure from manifold I15 to lines920 and 92 leading to the above described rivet gate or selectorcylinder 90. It will be seen that energization of stage A results inshifting of the dimpling shoe 41 into alignment with the main ram anddelivery of a rivet into passage 81 of the rivet feed means.

A selector switch I62 is provided to either condition the internalelectronic circuit for the full sequence of operations of the machine orfor punching only, or for riveting only as desired. The switch I62 isinterposed between the posts or terminals B C and D of stages B, C andD, and certain external contacts embodied in the machine. A line I63extends from post B to a post of the switch I62 and the related switchblade I64 is engageable therewith to complete a circuit through a line I65 extending to an external contact I66. As illustrated in Figure 13,contact I66 is in the nature of a post extending through a tubularinsulating screw 300 which in turn is threaded through an opening in thehead of the left hand shift cylinder 63. The inner end of the contactI66 is engageable by piston 65.

The next phase of the operation is effected by engagement of theleft-hand shift piston 65 with the above described contact I66. ContactI66 is connected with terminal B of the first intermediate stage throughthe medium of line I65 and selector switch blade I64 so that engagementof the piston with the contact I66 grounds this circuit and thus rendersthe tube I25 conductive. The timing switch I2I of stage B is open atthis time, and the maximum timing circuit I40I4I allows ample time forthe grounding of circuit I64 and I65 as just described. The conductivetube I25 energizes relay I 28 and contactor I 33 comes into engagementwith terminal 13 This energizes a relay I11 having a contactor I18interposed in a lead I19 extending from a solenoid actuated four-wayvalve I to a common A. C. power lead I91. Valve I 80 controlscommunication between the air pressure manifold I15 and a line I8I, andcommunication between the line I8I and the atmosphere. Line I8I extendsto one end of a diaphragm valve I04 illustrated in detail in Figure 5.

Diaphragm valve I04 includes a tubular body I82 provided at its endswith caps or heads I63.

A partial partition in the body carries a tubular seat member I99 anddefines two end chambers I95 and I99. The memberIB I extends into thesechambers and its end surfaces constitute annular seats which oppose theheads I93. Flexible diaphragms I97 and I99 are secured against the endsof the body I92 to extend acrossthe chambers I85 and I89. The diaphragmsare movable into and out of engagement with the adjacent ends of theseat member I84. An exhaust port I89 communicates with the inner portionof chamber I89 and an air pressure supply line I99, leading frommanifold I75, communicates with the inner portion of chamber I95. Itwill be observed that the effective areas of the diaphragms I87 and I88exposed to pressure introduced into the outer ends of the chambers I95and I85, are considerably larger than the areas of the diaphragmsexposed at the interior of the seat member I99 and the areas exposedaround the seat member. Accordingly, pressure admitted to the outer endof a chamber holds the related diaphragm I97 or I98 engaged with theseat member I99 and resists comparable pressure within the seat memberI89 or within the annular space surrounding the seat member. Release ofpressure from an outer end of a chamber I85 or I 98 allows the relateddiaphragm to open away from the seat member. A pipe I99= communicateswith the interior of the seat member I84 and extends to the upper end ofthe main cylinder 69.

When relay I77 is energized to reverse the solenoid actuated valve I89,pressure is relieved from line I8I and the outer end of chamber I85.This allows diaphragm I87 to move to the open position so that air underpressure pipe I99 flows through pipe I99 to the upper end of the maincylinder 99. Substantially simultaneously with this action, air underpressure is supplied to the outer end of chamber I96 to close thediaphragm I98 against seat member I89 and thus close off the exhaustI89.

The means for effecting reversal of diaphragm I99 includes a relay I9Ienergized upon actuation of relay I77. A lead I92 extends from the coilof relay I9I to the power supply I22 and the above described relay I77has a contactor and pole combination interposed in lead I92. Thus, uponenergization of relay I77, relay I9I is also energized. Relay I9Icontrols a four-way solenoid actuated valve I93. Relay I9I has a bladeand pole I95 interposed in a lead I96 extending from the supply line I97to the solenoid of valve I93 so that energization of the relay operatesor reverses the valve. Valve I93 governs a pipe I94 leading to the outerend of diaphragm valve chamber I89 to either connect the same with airpressure supply manifold I75 or the atmosphere. Energization of relayI9I reverses valve I93 so that air under pressure is supplied to pipeI94 and chamber I99. It will be seen that upon firing of tube I25,valves I89 and I93 are reversed to reverse the diaphragm valve I94 sothat air under pressure is supplied to the upper end of the maincylinder 99 to actuate the ram 68 downwardly.

In accordance with the invention, means is provided for limiting theinitial downward stroke of the main ram 98 so as to control the depth ofthe dimple formed in the work W, and the strokelimiting means serves toinitiate operation of the intermediate electronic stage C. A dimpledepth contact is provided in the lower portion of the main cylinder 59to be engaged by ,thepiston 79 as it descends. A plate I98 of dielectricmatepower supply I22.

rial is secured to the under side of cylinder69 and carries a bushingI99. A tubular thumb screw 299 is threaded upwardly through the 'bushingand passes freely through an opening in the cylinder wall to enter thecylinder. An elongate contact stem 29I is slidable in the thumb screw299 and has a. head at its lower end for contacting the under side ofthe thumb screw knob. A spring 292 is engaged under compression betweenthe screw 299 and a head on the upper end'of the stem 29I to urge thestem upwardly. It will be seen that rotation of the screw 299 verticallypositions or adjusts the contact stem 29I. The knob of the screw 299 isconveniently accessible at the front of the machine so that the operatormay readily vary or regulate the depth of the dimples to be formed.

A lead or conductor 293 is electrically connected with the contact stem29I through the medium of the bushing I99 and screw 299, and extends tothe post C of the intermediate'electronic stage C. When the main piston79 moves into engagement with the contact stem 29I, the grid circuit ofstage C is grounded to make the tube I25 conductive. This in turnenergizes relay I28 to bring the blade I33 into contact with post C Aline 295 extends from terminal C to a relay 299, a circuit forenergizing relay 295 being completed through lead 295, contactor I93 andpost C Relay 299 includes a post and contactor 297 interposed in a lead298 extending from power line I97 to oneside of the solenoid of afour-way valve 299. The other side of this solenoid is tapped into line2I9 extending to the Valve 299 governs the above mentioned pipes 99 and49 which lead to the upper and lower ends respectively of the punchoperating cylinder 29. When the solenoid of valve 299 is in the normalde-energized condition, the valve connects the pipe 99 with an airpressure supply line 2I2 so that the piston 29 is held in the upperposition. Upon reversal of the valve 299, effected by operation of relay299, pipe 49 is put into communication with pressure line 2I2 and pipe99 is allowed to exhaust to atmosphere. This actuates piston 29downwardly and the punch 29 is forced upwardly to form an opening in thedimpled work piece. It is to be observed that air pressure is maintainedin the main cylinder 99 at this time and the work W-is tightly clampedbetween the dies I7 and 59 as it is punched. This assures the productionof a true clean opening in the work with a minimum of distortion.

As described above, slugs S of the sheets or work pieces W are pushedupwardly through the opening of die 59 when the punch is operated. Theinvention provides for the delivery of air under pressure to the nozzleI92 to blow these slugs free. The above mentioned line or pipe supplyingthe air nozzle I 92 is in communication with the pipe I94 which extendsbetween solenoid operated valve I93 and diaphragm valve I99. When thevalve I99 is reversed te-close off the exhaust I99 of the diaphragmvalve as previously described, air under pressure is also supplied tothe nozzle I92 through line I93. A stream of air discharges from thenozzle I92 at a substantial velocity so long the solenoid of valve 699remains energized. Accordingly, the slugs S formed during the punchingoperation are blown clear through the opening IEiI by the air blast asthe punch approaches the upper end'of its stroke.

At the instant the blade or contactor I33 of stage C is operated towardpost the circuit to the coil of relay of I1! is opened to de-energizethe relay Ill. The current to relay IT! is carried by relay I28, line2I'I, relay I28 and a line 500 extending from post 13' to the winding ofthe relay. When relay I28 is energized as just described, this circuitis broken between terminals C and C De-energization of relay III causesreversal of solenoid operated valve I80, which in turn seals off bothends of the diaphragm valve I04 to lock the ram 66 in its down ordimpling position. When blade I33 moves into engagement with terminal Ca circuit is completed to the winding of relay 206 through lead 205.Energization of relay 203 energizes solenoid actuated valve 209 tosupply air under pressure to cylinder 28 through line 40. This actuatesthe punch to form an opening in the work pieces W.

The above described actuation of the punch 20 causes operation ofelectronic stage D, which in turn ole-energizes relays I9I and 205. Asshown in Figure 4, a rod 22I is attached to the cylinder 28 of the punchoperatin mechanism and a sleeve 222 is slidable on the rod. The sleeveis yieldingly urged upwardly by a spring 223. A projecting arm on thesleeve 222 carries an insulated contact 224 in position to be engaged bythe lever 32 when the punch 20 reaches the upper end of its movement. Aconductor 225 extends from contact 224 to the terminal D of stage D.Upon engagement of the lever 32 with contact 224, the grid circuit oftube I is grounded to discharge condenser I and the tube is madeconductive. This energizes relay I28 to break the connection betweenterminals D and D This in turn de-energizes relays I9I and 206.Deenergization of relays I9I and 206 results in reversal of the solenoidoperated valves I93 and 209 so that the spring TI is free to restore thepiston I0 to its raised position and to move the ram upwardly out ofengagement with the die 50. Valve 209 is also reversed to cause thepunch 20 to descend. Relay III remains energized at this time to holdvalve I14 in the actuated position so that the dimpling die remains inline with the ram 68. Relay III is locked in by a lead 226, tapped intothe interconnecting line 2I6 and extending to a second contactor 221 ofthe relay, the contactor being connected with a pole of the relaywinding.

The invention provides means whereby restoration of the ram 68 reversesthe positions of the dimpling shoe 41 and the riveting shoe 48. Atubular screw 229 is adjustably threaded through a bushing 230 securedin a cli-electric plate on the hood I8 of the main cylinder 69. Acontact stem 23I is shiftable in the screw and extends downwardly intothe hood. A sprin 232 is engaged between the screw 229 and a head on thelower end of the stem 23I to urge the stem downwardly to its lowermostposition. The stem 23I is engaged by the upper end of the rod I5 whenthe piston I0 returns to its upper position. A conductor or line 233extends from a post on the bushing 230 to the terminal E of stage E.When the contact stem 23I is engaged by the rod I5, the control gridcircuit of stage E is grounded so that tube I25 becomes conductive toenergize relay I28 This breaks the connection between terminals E and Eand relay III is de-energized so that valve I74 is reversed. Reversal ofant actuation of piston I65 shifts the dimpling shoe 4! to an idleposition and moves the riveting button or shoe 48 carrying thepreviously introduced rivet into alignment with the main ram 68. It willbe observed that at this time all external relays are de-energized. Themachine is now in condition for the rivetin operation.

Shifting of the riveting shoe 48 to the active position is immediatelyfollowed by downward actuation of the main ram 68. The means foraccomplishing this includes a contact 234 carried by an insulating screw235 threaded through an opening in the end of the right-hand shiftcylinder 64 so as to be engageable by the piston of that cylinder whenit returns to the outer position. A conductor or line 235 is connectedto contact 234 and extends to terminal F of stage F. Engagement of thereturning piston with contact 234 grounds the control circuit of stage Eto render the tube I25 conductive so that relay I28 is energized. Inaccordance with the invention, this re-energizes or reverses thefour-way valves I80 and I93. The means for accomplishing this operationincludes a relay 238 having a blade 239 interposed in a line 240extending from the A. C. power line I91 to one pole of the solenoidoperated valve I80. The relay has a second blade 24I in a line 242extending from the A. C. power line I91 to the line I96 of the solenoidoperated valve I93. A conductor 243 extends from the terminal F to stageF to the winding of relay 238 so that energization of relay I28energizes relay 238 and operates valves I80 and I93. In accordance withthe previous description of operation, actuation of the valves I00 andI93 supplies air under pressure to the upper end of the main cylinder 69 through the medium of the diaphragm valve I04. This operates the ram68 downwardly to drive or upset the rivet releasably held in the shoe48. As shown in Figure 7, the rivet is passed through the punchedopening in the work W and its shank is upset against the upper end ofthe punch 20 and the surface of die The invention provides adjustablemeans for accurately determining the depth of the rivet and forinitiating the next stage of operation. This means includes what we willterm a rivet depth contact 244 positioned to be engageable by the mainpiston 10. A tubular thumb screw 245 is threaded through a bushing 246in the insulating plate I93 and passes freely into the lower end of thecylinder 89 as best shown in Figure 12. The rivet depth contact 244 isin the nature of an elongate stem shiftable in the screw 245 andprovided with heads at its upper and lower ends. A spring 241 is engagedbetween the upper head of the contact and the screw 245 to urge thecontact to its upper position projecting a considerable distance beyondthe screw. The contact 244 is at a lower elevation than the dimple depthcontact stem 20I and is not engaged during the dimpling stroke of theram 68. As the piston I0 moves downwardly during the riveting stroke, itengages and depresses the stem 20I, but at this time the circuitsassociated with the stem are idle. A lead 248 extends from a screw orpost on a bushing 246 to the terminal G of electronic stage G. When thepiston I0 engages the stem 244, the control grid circuit of tube I25 isgrounded and the tube is made conductive. This energizes relay I28 sothat its blade I33 moves out of engagement with terminal G As a result,th circuit to terminal F and line 243 is broken to de-energize relay238. This de-energizes or reverses valve I80 and I93 so that thediaphragm valve I04 operates to cut off theairsupply to the maincylinder 69 and to exhaust .air therefrom. The spring TI restores thepiston "It! and ram 58 to their upper positions. It will be observedthat the operator may accurately time the operation just described byadjusting the thumb screw 2'55 and thereby regulate or determine thedepthof the driven rivet. Upon operation of stage G, the blade I33 ofits relay I moves out of engagement with terminal G This clears D. C.current'from all external. relays ll'I, Ill, lei, 2&6 and2238.

The reset stage 1-1 ofthe electronic system .is operated substantiallysimultaneously with return of the ram 63. Theswitch 138 .of stage G isclosed at all times, and upon .energization of relay I28as abovedescribed,.timingcircuit is? and MD times-out .the :tube 1 22 of stageWhen the charge in condenser M9 is reduced to a given degree, the tubeI42 becomes conductive to energize relay 1%. Operation of .relay Hi8breaksthe DCcircuit 120-150 todeeenergize the relays ,IIB, .l28, 4281130 .t28 inclusive, of the electronic system. lhe contactor of .relayIE8 moves to thepole l'rtllto apply .full negative bias voltage .to thetiming condensers. LEA, .149 and l lll to 148 inclusive,.to preventthetubes of the. several stages :from becoming conductive when voltage .-is.again. applied ;.to the system. Thus the electronic system :is .fully.restored .for the next operation.

The machine .maybe conditioned. to perform given. individual. operations1 or. a sequence .of; selectedsoperationsshort ;of .a. full sequentialcycle. For'examplathe machine may .be .set to :dimple the-work W andpunchen. openingthereinzfor the subsequent, reception of axrivet. Theabove mentioned selectorswitch I 62 is embodied in the external circuitto provide for the performance of selectedoperations orsequence ofoperations. The selector switch includes the previously mentionedv.blade I66, and additional blades 25,:25I and 2 52. Figural? showstheselectorswitch :in position fora full sequence cycle of the machine.When desired to only dimple and punch the work .W, the selector switchis moved :to .a position ..where,its blades 250,,2'5I and 252 functionas ,describedbelow.

In considering the following description of operation where the machineis employed for dimpling and punching only or for rivetinserting ,anddriving ,onlyn the relationship between the yresistances in the controlgrid circuits of the severalelectronic stagesiis of importance. Whenthe, relay I 28 of. axgiven. stage is .open orin the initial position,.the resistance in the circuit from the condenser I to the line Ilfiisless than the resistance in the circuit from the condenser to theterminal B ,C. ,.D etc., as the case may be. Accordingly, the tubel25 isnot made conductive, even thoughthis terminalis grounded by theoperation of. some external element of the machine. The relay 528 ofaprecedingelectronic stage must be energized or closed tovrender thetube I25 conductive by the grounding of the control grid circuit throughthe related terminal B C D etc. The resistance I21 adjacent the terminalis of such a value'that upon grounding of the circuit, the related tubeI25 is made conductive almost immediately by bleedin 01f the charge inthe associated condenser I40.

Thedimpling and punching cycle is initiated in the same manner as thefull sequential cycle by closing switches I54, I and I57. This resultsin operation of electronic stage A to shift dimple die :31 into positionbetween die VI! and ram es. Stage B than operates automatically tosupply air under pressure to the upper end of the main cylinder 69 tomovethe ram downwardly whereby a dimple is formed in the work W by thedies It and 5.3. The dimple depth contact 235 is engaged by the pistoniii] to operate stage C at the completion of the dimpling operation.Actuation of stage C maintainsair pressure in the main cylinder 69 andcausesair under pressure'to be supplied to cylinder 28 to actuate thepunchlfl. The punch 20 forms an opening in the material held by the diesII and At the completionof the punchingopflration, lever 32 engagescontact 224 to energize orifire electronic stageD, which in turneifectsthe ;return of the ram 68 and punch '20 to their idle positions. Pistonit comes into engagement with contact 223i as the rain approaches itsuppermost position, and electronic stage E'is operated. This causes therivet shoe 48 to move into position between the ram 68 and die 17.However, there is no rivet contained in the shoe 48 at this time, andthe shoe-is not broughtinto-operation dur t i ns a p nchin s quenceBlade 252 of the selector switch lfifl is connected between a lead 25dextending from power line Iii?! and a line 255extend ng to one side ofthe solenoid operated three-way valve 93. Whenthe selector switch ispositioned for dimpling and punching only, the blade252 closes the-cirit just mentioned to operate the valve-93 to a pgsition where the airpressure ;.supply is out -eii from-the rivet gate cylindertl). The rivetgate is thus held in a position where rivets cannot feed into the shoed8.

Electronic stage F is grou-nded by the selector switch to fireimmediately upon'the operation of the electronic stage E, and before therighthand shifting piston engages contact 23 3. Electronic stage G isalso fired immediately. Contact 25I of the selector switch is-at thistimepositioned to ground a tap 256 from the line 2 38 extending toterminal G Electronic stage G clears .all the external relays of thesystem andserves'to time-out tube I42 of stageH through circuit I31 lSE-and IM This clears out-the electronic circuits for the succeedingoperation.

When the machine is to be used to insert-rivets in previously dimpledandpunched -openingsin the work piece and then to drive the rivets, theselector switch I52 ismoved to the rivetonly position where the blades I36, 2-5d-and Zircontrol the related circuits. In carrying out the rivetonly operation, electronic stage A is operated by closing switch I5d andthe other switches in the initiating circuit. This fires'or operatesstage Aas above described. lNith selector switch I62 in the rivet onlyposition, the blade I84 engages a terminal to place a resistor 266 inthe circuit E55 which connects terminal B and contact I66 at theleft-hand shiftcylinder E3. The resistor 26% is of such a value that itdelays firing of tube. I25 of stage B:fora sufficient time to allow therivet to drop into-the shoe 53 from the passagegfi'I. The automaticrivet only cycleissubstantially reduced in-tiine by reason of the factthat stages C and D areimmediately grounded out, as will be describedbelow. This shortening of the-cycle of operation is compensated for'bythe delay in the firing of stage B effected by resistorltfl, and therivet is given ample time to fall into the rivet shoe before the shoe isshifted. Engagement or shift piston 65 with contact I66 results infiring of stage B as described above. This conditions stage C foroperation, and blade 250 of the selector switch 162 grounds line 203 sothat stage C fires immediately. This conditions stage D, which als firesimmediately because blade 25! of the selector switch grounds line 225leading to the terminal D Thus stages C and D are oper ated in rapidsuccession and do not depend upon external circuit conditionsestablished by machine operation for their actuation. Stage E of theelectronic system operates as above described to cause the rivet shoe 48carrying the rivet to be shifted into position in line with the main ram68. Stage F then operates as previously described to actuate the mainram, and the rivet is driven. Electronic stage G operates at thecompletion of the rivet driving operation by reason of the engagement ofpiston 16 with the rivet depth contact 244 and actuation of stage Gcauses the main piston and ram 68 to return to their upper positions.Re-set stage H operates as in the previously described cycles, and thesystem is restored to the normal condition for the next rivet onlysequence. The machine may be repeatedly operated to insert and driverivets in previously dimpled and punched openings by merely actuatingthe foot switch I54.

Switches I21, I38 and I38 to I38 inclusive may be omitted if desired.However, they are illustrated in the preferred embodiment of theinvention to indicate that the successive stages of the electronicsystem may be timed out to perform or permit the perfomance of specialor selected machine operations as conditions may require.

From the above detailed description it will be seen that we haveprovided a fully automatic riveting machine that may be employed tocarry out a complete sequence of operations, including the dimpling andpunching of the work parts, the insertion of the rivets and the drivingof the rivets. The machine may also be set to simply dimple and punchthe work parts or to insert rivets in previously dimpled and punchedopenings and then drive the inserted rivets. Thumb screw 200 may beeasily adjusted to regulate the depth of the dimples to be formed in thework pieces, and thumb screw 245 may be manipulated to regulate thedepth of the rivets. The thumb screws 200 and 245 are located where theyare conveniently accessible to the operator, and adjustment of themachine may be accomplished without any delay whatsoever. It is to beobserved that the several primary or active elements of the machine aredirectly operated by cylinder and piston mechanisms, and there are nointervening linkages subject to wear and malfunctioning. The electroniccontrol system assures properly timed sequential operation of theseveral machine parts and is such that simple setting of the selectorswitch I62 conditions the machine either for the performance of the fullcycle of operations or for dimpling and punching only, or riveting only.The invention provides a trouble-free fully automatic machine capable ofrapidly carrying out its several functions.

Having described only a typical form of the invention, We do not wish tobe limited to the specific details herein set forth, but wish to reserveto ourselves any variations or modifications that may appear to thoseskilled in the art and/ or fall within the scope of the followingclaims.

We claim:

1. In a riveting and dimpling machine, anvil means carrying a die, aram, a piston for moving the ram toward the die, a shoe shiftablebetween a retracted position and a position in alignment with said ramand die and capable of movement toward the die, a second die carried bythe shoe, cylinder and piston means for shifting the shoe between saidpositions, means for initiating operation of the first named piston tocause the ram to move said second die against a work piece on the firstnamed die including contact means associated with said cylinder andpiston means and closed when the shoe reaches the position in alignmentwith the ram, and means for terminating movement of the ram toward theanvil to limit the effect of the dies on the work piece comprising anelectric control means and contact means for the same operated by saidfirst named piston.

2. In a dimpling machine, anvil means carrying a die, a ram, a firstpiston for moving the ram toward the die, a shoe shiftable between aretracted position and a position in alignment with said ram and die andcapable of movement toward the die, a second die carried by the shoe,means for shifting the shoe between said positions including a cylinderand a second piston operable therein, means for initiating operation ofthe first piston to cause the ram to move said second die against a workpiece on the first named die including contact means associated withsaid cylinder and said second piston and closed when the shoe reachesthe position in alignment with the ram, means for terminating movementof the ram toward the anvil to limit the effect of the dies on the workpiece including an electric control system for said first piston and acontact operated by said first piston to govern said system, and manualmeans for changing the position of the contact to vary the efiect of thedies upon the work piece.

3. In a dimpling machine, anvil means carrying a die, a ram, a firstpiston for moving the ram toward the die, a shoe shiftable between aretracted position and a position in alignment with said ram and die andcapable of movement toward the die, a second die carried by the shoe,cylinder and piston means for shifting the shoe between said positions,means for initiating operation of the first named piston to cause theram to move said second die against a work piece on the first named dieincluding contact means associated with said cylinder and piston meansand closed when the shoe reaches the piston in alignment with the ram,means for terminating movement of the ram toward the anvil to limit theeffect of the dies on the work piece including an electric controlsystem, a contact in said system arranged to be engaged by piston tolimit movement of said first piston, and an accessible screw threadedmember manually operable to alter the position of the contact and thusalter the effect of the dies upon the work piece.

4. In a dimpling machine, a normally stationary die, a die supported formovement toward the stationary die, a ram vertically aligned with themovable die for moving the same toward the stationary die, a cylindervertically aligned with the ram, a piston operable in the cylinder toactuate the ram, and means for controlling the piston to determine thestroke of the ram and therefore the effect of the dies upon a work pieceengaged between them, said means including valve means for controllingthe delivery of actuating fluid pressure to the cylinder, an electricalsystem for operating the valve means and a contact in the systemarranged in the cylinder to be engageable 21 by the piston to causeclosing the valve when the dies have produced a giveneiiect upon thework p e e- 5'.In a dimpling machine having an anvil means carrying atubular dimpling die and having a punch movable through'the die,the-combination of a ram movable toward and away from the die, a;dimpling-shoe arranged for movement between-a retracted position and aposition in line with the ram and for movement toward and-awayirom-thedie,- cylinder and piston means for-moving '-the dimpling shoe intoalignment withthe ram, ache in thedimp'ling shoe, cylinder and pistonmeans for moving'the'ram toward the anvil means, means energized by thepiston of the-first 'riamed cylinder and piston means for supplyingactuating fluid pressure to the cylinder of the second'na'med cylinderand. piston means to actuate theram so tha't said dies form a dimple inawo'rklpiec'e, means'controlled by the piston of the ram actuating meansfor operating the punch to form an opening in the work piece, and meanscontrolled by the punch actuating means for moving the ram away from theanvil.

6. In a machine of the class described for dimpling and punching a workpiece, a stationary die, a shiftable die, means for shifting the seconddie into alignment with the first die, a ram for moving the second dietoward the first die to form a dimple in the work piece, a punch movablethrough the first die to form an opening in the dimple, and anelectronic control for producing sequential operation of the dieshifting means, ram and punch on the order named, said control includingcontact means rendered active upon said shifting of the second die, afirst electronic stage operated by said contact means to cause actuationof the ram, contact means rendered active upon full actuation of theram, and a second electronic stage operated when the second contactmeans becomes active to cause actuation of the punch.

7. In a machine of the class described for dimpling and punching a workpiece, a stationary die, a shiftabl-e die, means for shifting the seconddie into alignment with the first die, a ram for moving the second dietoward the first die to form a depression in the work piece, a punchmovable through the first die to form an opening in the depression, andan electronic control for producing sequential operation of the dieshifting means, ram and punch in the order named, said control includinga first electronic stage manually initiated to cause actuation of thedie shifting means, a second electronic stage conditioned for operationupon operation of the first stage and operable to cause operation of theram, contact means operated upon said shifting of the second die tocause operation of the second stage, a third electronic stageconditioned for operation by said second stage and operable to causeactuation of the punch, and contact means operated upon actuation of theram to cause operation of said third stage.

8. In a machine of the class described for dimpling and punching a workpiece, a stationary die, a shiftable die, means for shifting the seconddie into alignment with the first die, a ram for moving the second dietoward the first die to form a dimple in the work piece, a punch movablethrough the first die to form an opening in the dimple, and anelectronic control for producing sequential operation of the dieshifting means, ram and punch in the order named, said control includinga first electronic stage manually ini- 22 tiate'd to cause actuation ofthe die "shifting means, a' s'econd electronic stage conditioned foroperation upon operation of the first stage and operable to causeoperation of the ram, contact means operated upon said shifting of the"second die to cause operation-of the second stage, a thirdelectronic-stage conditioned for operation by said second stage andoperable to cause actuation of the punch, and 'contact means ope'ratedupon actuation'of the 'ram' to cause operation of said third stage, eachof said stages including a relay controlling the element which thatstage operates and also operable to condition the succeeding stage, atube for energizing said relay and having a control grid circuitgrounded by one of said contact means to render the tube conductive toenergizethe-relay.

9. In a machine having a stationary die, a shiftable die and a ram formoving the shiftable die against a work piece-on the stationary die thecombination of means for shifting-the die into alignment with the ram,me'ans for operating the ram, and a control system comprising a firstelectronic stage including a re lay for operating the die shiftingmeans, a tube for energizing the relay and having a control gridcircuit, and manually operable means for controlling said circuit torender the tube conductive so as to operate the relay, and a second stae comprising a relay for causing actuation of the ram operating means, atube having a control grid circuit conditioned by operation of the relayof the first stage and contact means operated upon shifting of theshiftable die to the position where it is aligned with the ram forgrounding the grid to render the tube conductive.

10. In a machine having a stationary die, a shiftable die and a ram formoving the shiftable die against a work piece on the stationary die thecombination of; means for shifting the die into alignment with the ram,means for operating the ram, and a control system comprising a firstelectronic stage including a relay for operating the die shifting means,a tube for energizing the relay and having a control grid circuit, andmanually operable means for controlling said circuit to render the tubeconductive so as to operate the relay, and a second stage comprising arelay for causing actuation of the ram operating means, a tube havin acontrol grid circuit conditioned by operation of the relay of the firststage, said grid circuit including contact means actuated by said meansfor shifting the die to ground the grid circuit to render the tubeconductive upon shifting of the shiftable die to the position where itis aligned with the ram.

11. In a machine having a stationary die, a shiftable die and a ram formoving the shiftable die against a work piece on the stationary die, thecombination of; means for shifting the die into alignment with the ram,means for operating the ram, and a control system comprising a firstelectronic stage including a relay for operating the die shifting means,a tube adapted to be made conductive to energize the relay, a gridcircuit for the tube normally imposing a negative bias to hold the tubenonconductive, manually operated means for controlling said grid circuitto render the tube conductive to produce actuation of the die shiftingmeans, and a second stage including a relay for causing actuation of theram operating means, a tube operable when conductive to energize thesecond stage re- 23 lay, a control grid circuit for the second stagenormally connected with a bias source by the first stage relay anddisconnected therefrom upon operation of the first stage relay, acondenser in the second stage grid circuit maintaining a sufficient biascharge to hold the second stage tube non-conductive, and contact meansfor grounding the second stage grid circuit upon shifting of theshiftable die into alignment with the ram to bleed said charge from thecondenser to render the second stage tube conductive.

WAYNE E. HARNESS- JOHN O. HRU'BY, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,063,691 Marchant Dec. 8, 19362,069,042 Marchant Jan. 26, 1937 Number Name Date Oeckl et a1. Oct. 1,1940 Weingold Feb. 4, 1941 Hagedorn Dec. 22, 194 Ward Dec. 29, 1942Fluke Jan. 5, 1943 Hill Apr. 6, 1943 Merriman Sept. 7, 1943 Ward Feb. 8,1944 Mayer et a1 Aug. 22, 1944 Rechton et a1 Mar. 27, 1945 Speller May8, 1945 Grifiin Mar. 16, 1948 Christensen Mar. 30, 1948 Johndrew Dec.14, 1948 Fischer Jan. 4, 1949 OTHER REFERENCES The article on pages 323and 324 of the Review 20 of Scientific Instruments, November 1939, vol

ume 10.

